Bulk viscosity of strange quark matter: Urca versus non-leptonic processes

A general formalism for calculating the bulk viscosity of strange quark matter is developed. Contrary to the common belief that the non-leptonic processes alone give the dominant contribution to the bulk viscosity, the inclusion of the Urca processes is shown to play an important role at intermediate densities when the characteristic r-mode oscillation frequencies are not too high. The interplay of non-leptonic and Urca processes is analyzed in detailComment: 9 pages, 4 figures, v2: revised figures, no change in result

Nonlinear Realization of the Local Conform-Affine Symmetry Group for Gravity in the Composite Fiber Bundle Formalism

A gauge theory of gravity based on a nonlinear realization (NLR) of the local Conform-Affine (CA) group of symmetry transformations is presented. The coframe fields and gauge connections of the theory are obtained. The tetrads and Lorentz group metric are used to induce a spacetime metric. The inhomogenously transforming (under the Lorentz group) connection coefficients serve as gravitational gauge potentials used to define covariant derivatives accommodating minimal coupling of matter and gauge fields. On the other hand, the tensor valued connection forms serve as auxillary dynamical fields associated with the dilation, special conformal and deformational (shear) degrees of freedom inherent in the bundle manifold. The bundle curvature of the theory is determined. Boundary topological invariants are constructed. They serve as a prototype (source free) gravitational Lagrangian. The Bianchi identities, covariant field equations and gauge currents are obtained.Comment: 24 pages. to appear in IJGMM

Gluonic phases, vector condensates, and exotic hadrons in dense QCD

We study the dynamics in phases with vector condensates of gluons (gluonic phases) in dense two-flavor quark matter. These phases yield an example of dynamics in which the Higgs mechanism is provided by condensates of gauge (or gauge plus scalar) fields. Because vacuum expectation values of spatial components of vector fields break the rotational symmetry, it is naturally to have a spontaneous breakdown both of external and internal symmetries in this case. In particular, by using the Ginzburg-Landau approach, we establish the existence of a gluonic phase with both the rotational symmetry and the electromagnetic U(1) being spontaneously broken. In other words, this phase describes an anisotropic medium in which the color and electric superconductivities coexist. It is shown that this phase corresponds to a minimum of the Ginzburg-Landau potential and, unlike the two-flavor superconducting (2SC) phase, it does not suffer from the chromomagnetic instability. The dual (confinement) description of its dynamics is developed and it is shown that there are light exotic vector hadrons in the spectrum, some of which condense. Because most of the initial symmetries in this system are spontaneously broken, its dynamics is very rich.Comment: 33 pages, RevTeX; v.2: Published PRD versio

Color-flavor locked superconductor in a magnetic field

We study the effects of moderately strong magnetic fields on the properties of color-flavor locked color superconducting quark matter in the framework of the Nambu-Jona-Lasinio model. We find that the energy gaps, which describe the color superconducting pairing as well as the magnetization, are oscillating functions of the magnetic field. Also, we observe that the oscillations of the magnetization can be so strong that homogeneous quark matter becomes metastable for a range of parameters. We suggest that this points to the possibility of magnetic domains or other types of magnetic inhomogeneities in the quark cores of magnetars.Comment: 12 pages, 3 figures. Version accepted for publication in Phys. Rev.

Bulk viscosity of spin-one color superconductors with two quark falvors

We consider the contribution of the Urca-type processes to the bulk viscosity of several spin-one color-superconducting phases of dense two-flavor quark matter. In the so-called transverse phases which are suggested to be energetically favorable at asymptotic densities, the presence of ungapped quasiparticle modes prevents that spin-one color superconductivity has a large effect on the bulk viscosity. When all modes are gapped, as for one particular color-spin-locked phase, the effect on the viscosity can be quite large, which may have important phenomenological implications.Comment: 10 pages, 6 figures, Discussion is extended and several references added. Version accepted for publication in Phys. Rev.

Modernization of the pulse shape discrimination method for neutron and gamma quanta in scintillation detector

In this paper, we investigated the efficiency of several known and new methods of digital pulse shape discrimination for neutrons and gamma quanta. Experimental data were obtained on a setup consists of a Pu-Be neutron source, organic p-terphenyl scintillation detector and 14 bits, 500 MHz sampling rate flash-ADC with capability to store and upload to the host computer long waveforms for further analysi

SOME PROPERTIES OF THE KERR SOLUTION TO LOW ENERGY STRING THEORY

The Kerr solution to axidilaton gravity is analyzed in the Debney--Kerr--Schild formalism. It is shown that the Kerr principal null congruence retains its property to be geodesic and shear free, however, the axidilatonic Kerr solution is not algebraically special. A limiting form of this solution is considered near the ring-like Kerr singularity. This limiting solution coincides with the field around a fundamental heterotic string obtained by Sen.Comment: 14 pages., LaTe

Complex Kerr Geometry, Twistors and the Dirac Electron

The Kerr-Newman spinning particle displays some remarkable relations to the Dirac electron and has a reach spinor structure which is based on a twistorial description of the Kerr congruence determined by the Kerr theorem. We consider the relation between this spinor-twistorial structure and spinors of the Dirac equation, and show that the Dirac equation may naturally be incorporated into Kerr-Schild formalism as a master equation controlling the twistorial structure of Kerr geometry. As a result, the Dirac electron acquires an extended space-time structure having clear coordinate description with natural incorporation of a gravitational field. The relation between the Dirac wave function and Kerr geometry is realized via a chain of links: {\it Dirac wave function $\Rightarrow$ Complex Kerr-Newman Source $\Rightarrow$ Kerr Theorem $\Rightarrow$ Real Kerr geometry.} As a result, the wave function acquires the role of an ``order parameter'' which controls spin, dynamics, and twistorial polarization of Kerr-Newman space-time.Comment: 12 pages, 3 figs. Talk at the conference QFEXT'0

Понятие конкурентоспособности продукции в современных условиях

У роботі досліджується суть поняття конкурентоспроможності продукції підприємства в сучасних умовах. Зосереджено увагу на недоліках визначення цього поняття різних авторів. Викладено власні погляди до розуміння конкурентоспроможності продукції та сформульовано власне визначення цього поняття.This article enlightens essence of concept of competitiveness of products of enterprise in the modern terms. Concentrated attention on the defects of determination of this concept of different authors. Expounded own looks to understanding of competitiveness of products and worded own determination of this concept.В работе исследуется суть понятия конкурентоспособности продукции предприятия в современных условиях. Сосредоточено внимание на недостатках определения этого понятия разными авторами. Изложены собственные взгляды к пониманию конкурентоспособности продукции и сформулировано собственное определение этого понятия

Forms and Methods of Work of a Psychologist to Overcome Cyberbullying in Adolescent Students

В статье представлены результаты опытно-экспериментального исследования эффективности форм и методов работы психолога по преодолению кибербуллинга посредством развития копинг-стратегий, рефлексивности и эмпатии.The current article presents the results of the experimental research of psychologist’s forms and methods of working with teenagers to adress the issue of cyberbulling in terms of effectiveness, using coping strategies, reflection and empathy